1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . P O O L _ L O C A L --
10 -- Copyright (C) 1992-2001, Free Software Foundation, Inc. --
12 -- GNAT is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNAT; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNAT was originally developed by the GNAT team at New York University. --
31 -- Extensive contributions were provided by Ada Core Technologies Inc. --
33 ------------------------------------------------------------------------------
36 with System.Storage_Elements;
37 with System.Address_To_Access_Conversions;
39 package body System.Pool_Local is
41 package SSE renames System.Storage_Elements;
42 use type SSE.Storage_Offset;
44 Pointer_Size : constant SSE.Storage_Offset := Address'Size / Storage_Unit;
45 Pointers_Size : constant SSE.Storage_Offset := 2 * Pointer_Size;
47 type Acc_Address is access all Address;
48 package Addr is new Address_To_Access_Conversions (Address);
50 -----------------------
51 -- Local Subprograms --
52 -----------------------
54 function Next (A : Address) return Acc_Address;
55 -- Given an address of a block, return an access to the next block
57 function Prev (A : Address) return Acc_Address;
58 -- Given an address of a block, return an access to the previous block
65 (Pool : in out Unbounded_Reclaim_Pool;
66 Address : out System.Address;
67 Storage_Size : SSE.Storage_Count;
68 Alignment : SSE.Storage_Count)
70 pragma Warnings (Off, Alignment);
72 Allocated : constant System.Address :=
74 (Memory.size_t (Storage_Size + Pointers_Size));
77 -- The call to Alloc returns an address whose alignment is compatible
78 -- with the worst case alignment requirement for the machine; thus the
79 -- Alignment argument can be safely ignored.
81 if Allocated = Null_Address then
84 Address := Allocated + Pointers_Size;
85 Next (Allocated).all := Pool.First;
86 Prev (Allocated).all := Null_Address;
88 if Pool.First /= Null_Address then
89 Prev (Pool.First).all := Allocated;
92 Pool.First := Allocated;
101 (Pool : in out Unbounded_Reclaim_Pool;
102 Address : System.Address;
103 Storage_Size : SSE.Storage_Count;
104 Alignment : SSE.Storage_Count)
106 pragma Warnings (Off, Storage_Size);
107 pragma Warnings (Off, Alignment);
109 Allocated : constant System.Address := Address - Pointers_Size;
112 if Prev (Allocated).all = Null_Address then
113 Pool.First := Next (Allocated).all;
114 Prev (Pool.First).all := Null_Address;
116 Next (Prev (Allocated).all).all := Next (Allocated).all;
119 if Next (Allocated).all /= Null_Address then
120 Prev (Next (Allocated).all).all := Prev (Allocated).all;
123 Memory.Free (Allocated);
130 procedure Finalize (Pool : in out Unbounded_Reclaim_Pool) is
131 N : System.Address := Pool.First;
132 Allocated : System.Address;
135 while N /= Null_Address loop
138 Memory.Free (Allocated);
146 function Next (A : Address) return Acc_Address is
148 return Acc_Address (Addr.To_Pointer (A));
155 function Prev (A : Address) return Acc_Address is
157 return Acc_Address (Addr.To_Pointer (A + Pointer_Size));
160 end System.Pool_Local;